KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 187 



The girdle is premedian in position, lying at about 0.3 of the total length of the body from 

 the anterior end. It is narrow, shallow, and is disjilaced about half its own width. The anterior 

 flagellar pore opens at its jiroximal junction with the .sulcus, and the posterior pore midway 

 between the girdle and antapex. The narrow, shallow sulcus invades the epicene to the apex. 

 Below the girdle it extends posteriorly in a straight line, traversing about 0.7 of the distance 

 from the girdle to the antapex. 



The nucleus is elliptical in outline and centrally located with its major axis coinciding with 

 the long axis of the body. Its chromatin contents co\dd not be analyzed. Its major and minor 

 axes are about 0.6 and 0.4 transdiameters in length respectively. The cytoplasm is clear with 

 no large inclusions, but containing a number of oil globules and small, subspherical or irregular 

 bodies superficially ai'ranged. The surface is striate with equidistant, longitudinal striae about 

 equal in number on both epicone and hypocone and about 20 at the girdle across the ventral face. 



Dimensions. — Length, 65-78/^; transverse diameter, 29-38/^; clorsoventral 

 diameter, 3if^; axes of nucleus, 17/^ and 12/*. 



OccuEEExcE. — This species was first taken June 28, 1904, with a No. 20 net, 

 in a haul 10 miles off La Jolla, California, from 120 meters to the surface. It 

 was again found July 5, at the same distance offshore with the same apparatus, 

 in a haul from a depth of 240 meters to the surface. On July 7 of the same year 

 it was taken 11 miles off La Jolla in a surface haul. 



CoMPABisoxs. — This species belongs to the subgenus Lineadiuiiou, having 

 the thin periplast and striate surface of that group, but is unique in its lateral 

 compression and acute apices. 



Gymnodinium auratum sp. uov. 



Plate 2, figure 20; text figure Y, 13 



Diagnosis. — A small species with ovoidal l)ody, its length 1.44 transdiame- 

 ters; epicone conical; girdle submedian, displaced slightly more than its own 

 width; sulcus extending from apex to antapex; color old gold. Length, 62m. 

 Pacific off La Jolla, California, August. 



Description. — The body is broadh' ovoidal, nearly circular in cross-section, broadly rounded 

 posteriorly, conical anteriorly, its length 1.44 transdiameters at the girdle, the widest part. The 

 length of the epicone and hypocone are subequal, but, owing to its rotundity, the hypocone 

 exceeds the epicone in volume. The epicone is conical, about 70% with a narrowly blunt apex. 

 It has a length on the left and right sides of 0.43 and 0.54 of the total length of the body 

 respectively. The hypocone is broadly rounded, with smooth antapex. 



The girdle is submedian in position, its proximal and distal ends having a distance from the 

 apex of 0.43 and 0.54 of the total length of the body respectively. It is wide, about 0.09 trans- 

 diameter, and deeply impressed with smooth lips. Its course around tlie body is that of a left 

 descending shallow spiral, with its distal end displaced posteriorly slightly more than its own 

 width. The sulcus is a shallow, narrow channel, its width about 0.3 of the width of the girdle. 

 It extends from near the apex in a slightly sinuous course posteriorly to near the antapex. The 

 anterior flagellar pore opens at the proximal junction of the girdle and sulcus, the posterior 

 pore about two widths of the girdle posterior to the distal junction. 



The nucleus is a large, ellipsoidal body found on the left side of the hypocone. It is fill(>d 

 with fine, moniliform, chromatin strands arranged parallel to its long axis, which is slightly 

 oblique to the major axis of the body. Its major and minor axes are about 0.65 and 0.4 trans- 

 diameter in length respectively. 



